Prophylaxis angles (aka “prophy” angles or dental angles) are used by dental personnel to clean and/or polish teeth. Prophy angles generally include a body having a head, where the head has a central axis angled relative to a central axis of the body. The structural angle between the two central axes is normally 90°. However, other types of prophy angles, known as contra-angles, include a head angled from the body at an angle greater than 90°. Typically, the head of a contra-angle may be angled between about 10° to about 30° greater than 90° from the axis of the body. Contra-angles can be used by dental personnel for reaching difficult spots within the mouth of a patient. Prophy angles will usually have a dental bit, such as a prophy cup, a brush, and/or a bur, coupled at the end of the head that allows the dentist to clean and polish a patient's teeth.
Drive and driven gears are arranged within the body of the prophy angle in a meshing relationship in order to rotate the dental bit. In some devices, a cap slips over the driven gear and attaches to the body in order to secure the gears within the body. A portion of the driven gear usually extends out of an opening in the cap and provides a location where the dental bit can be attached. Once entirely assembled, the prophy angle can be coupled to a handpiece, such as a Doriot-type handpiece. Specifically, the body is slipped over the nose of the handpiece which has a collet adapted to receive the shaft of the driving gear. The collet holds the drive shaft against axial movement and connects the shaft to a motor adapted to rotate the driving gear which, in turn, rotates the driven gear and the dental bit.
In the past, dentists used non-disposable, metal prophy angles. While sturdy, metal prophy angles required extensive care to ensure against transferring disease and germs from one patient to another. If the metal prophy angle is not properly sealed, bodily fluids from a patient, such as saliva and/or blood, can penetrate the prophy angle. Simply wiping down the metal prophy angle between uses is not adequate sterilization. Rather, to achieve proper sterilization, the metal prophy angles must be autoclaved after each use and periodically disassembled and thoroughly cleaned in order to remove contamination. Cleaning the metal prohpy angles also removes any grit which may have penetrated the housing which, if not properly removed, might interfere with the gears and thereby reduce the operating life of the metal prophy angle or otherwise make it difficult to operate. Metal prophy angles also require periodic lubrication to ensure that the gears run smoothly, quietly, and efficiently to reduce heat build-up. Thus, the care required for metal prophy angles is quite extensive.
Due to the extensive care required by non-disposable prophy angles, plastic disposable prophy angles are desired by dentists. Disposable prophy angles are much more sanitary than non-disposable ones, and therefore more useful in preventing cross-contamination between patients. Moreover, their disposable nature eliminates the need to thoroughly sanitize, clean, and lubricate them between each use. While various types and configurations of disposable prophy angles have been made, it nonetheless remains beneficial to find improved disposable prophy angles that offer advantages over prior models.